Interleukins constitute an entire immune network that covers both innate and adaptive systems. Indeed, interleukins are classified into different families with their own characteristics and functions. Some of the interleukins have synergistic effects between them. Other interleukins cross-talk with each other. Nevertheless, these cytokines act in accordance with cascade signalling pathways. The structure, function, and biology of interleukins determine the role of these immune proteins relating to applied mechanisms and signalling pathways. These biomolecules are present in different conditions with a wide range of activities. Interleukins have an active role in immune responses to unsuitable conditions such as infectious diseases. Bacteria, fungi, protozoa, and viruses are able to activate different types of interleukins with different mechanisms. Moreover, viruses have very complicated situations in this regard. Oncogenic viruses may cause induction of those mechanisms which are involved both in infectious diseases and cancer.

In recent years, we are much more aware of their strategies, functions, structure, and importance in different infections and malignancies. In patients with different sicknesses and illnesses, an imbalanced condition may be identified in the production and function of interleukins. Therefore, the properties and characteristics, presence or absence of interleukin biomolecules can be recognized as a symptom of a particular disease, infection, and malignancy. Due to this fact, we can count on interleukins as invaluable biomarkers in versatile diseases such as infectious diseases. Moreover, the presence of mutations and polymorphisms in the genes of interleukins may lead to the appearance of a wide range of defects in humans with infectious diseases. This is due to interleukins controlling and governing a significant number of immune-related signalling pathways.

The aim of this Special Issue is to bring together original research articles about the role and importance of interleukins within infectious diseases. Review articles discussing the state of the art are also welcome.

Potential topics include but are not limited to the following:

• Molecular biology of interleukins
• Structural biology of interleukins
• The role of interleukins bacterial infectious diseases
• The role of interleukins in fungal infectious diseases
• The role of interleukins in protozoan infectious diseases
• The role of interleukins in viral infectious diseases
• The role of interleukins in oncogenic viruses
• Mutations in interleukins associated with infectious diseases